c-Abl激酶在中性粒细胞应答剪切力爬行进程中的分子行为及作用机制研究

Neutrophil crawling along the vascular endothelium is a critical step for the recruitment cascade that follows LFA-1-dependent adhesion and precedes emigration, and also important for the appropriate development of inflammation. Our previous studies confirmed that c-Abl kinase plays an important role in neutrophil crawling. c-Abl kinase is required for neutrophil recruitment to the inflammatory sites in vivo and crawling in vitro, and the inhibition of c-Abl kinase activity has a significant impact on neutrophil motive behavior. In addition, we found c-Abl kinase regulate membrane protrusion dynamics at the extended leading edges during neutrophil crawling. Based on our previous investigation, this study will focus on the neutrophil crawling under the intraluminal microenvironment, and establish a technological platform for living cell motility with fluorescent-labeled signaling molecules under physiological shear stress. FRET technique will be applied to describe the real-time molecular behavior of c-Abl kinase in the temporal and spatial distribution and dynamic conversion of kinase activity during the process of neutrophil crawling under shear stress. We will further study the active conversion effect of Vav1/Rac signaling axis through regulating the phosphorylation modification of Vav1 by c-Abl kinase. This work will reveal the central role and signal transduction mechanism of c-Abl kinase in regulating neutrophil crawling under physiological shear stress. The implementation of this project will possess important theoretical value for cell migration research in the field of molecular cell biology, and it will also provide potential targets for drug intervention and treatment of inflammation-related diseases.

中性粒细胞沿血管内皮爬行对于炎症的发生、发展至关重要。课题组前期研究工作证实c-Abl激酶在中性粒细胞爬行进程中发挥着重要作用，抑制c-Abl激酶活性严重影响中性粒细胞向炎症部位募集以及爬行能力，并且细胞膜褶皱样运动以及伸展速率明显减缓。本研究将以中性粒细胞爬行所处的血管腔微环境为切入点，建立反映生理状态剪切应力作用下并具有荧光标记分子动态示踪功能的活细胞运动研究技术平台，基于FRET技术描述剪切应力作用下c-Abl在中性粒细胞爬行运动进程中时空定位分布和活性动态转换的分子行为；深入研究c-Abl通过对效应分子Vav1的磷酸化修饰，从而调控Vav1/Rac信号轴的活性转换效应，揭示在生理剪切应力作用下以c-Abl为核心的调控中性粒细胞爬行的信号转导机制。本项目的实施不仅在细胞运动的分子细胞生物学研究方面具有重要的理论价值，同时也为炎症相关疾病的干预与治疗提供潜在的药物作用靶点。

中性粒细胞(Polymorphonuclear neutrophils，PMN)是参与早期炎症反应的重要免疫细胞之一。然而，PMN的免疫清除功能是一把“双刃剑”，在清除病原体的同时也会导致自身组织的损伤。在某些病理条件下，PMN向组织中大量而持续的浸润与多种炎症相关疾病的发生、发展及预后恶化有着密切关系，是急性肾损伤、支气管哮喘、脓毒症、类风湿性关节炎、急性肺损伤及急性呼吸窘迫综合征等发病的中心环节，适度抑制PMN的组织浸润成为治疗上述炎症相关疾病的新策略。因而，深入揭示PMN运动的分子机制、筛选干预PMN组织浸润的作用靶点，将具有重要的生理及病理意义。中性粒细胞沿血管内皮爬行对于炎症的发生、发展至关重要。课题组前期研究工作证实c-Abl激酶在中性粒细胞爬行进程中发挥着重要作用，抑制c-Abl激酶活性严重影响中性粒细胞向炎症部位募集以及爬行能力，并且细胞膜褶皱样运动以及伸展速率明显减缓。本研究以中性粒细胞爬行所处的血管腔微环境为切入点，建立反映生理状态剪切应力作用下并具有荧光标记分子动态示踪功能的活细胞运动研究技术平台，基于FRET技术描述剪切应力作用下c-Abl在中性粒细胞爬行运动进程中时空定位分布和活性动态转换的分子行为；深入研究了c-Abl通过对效应分子Vav1的磷酸化修饰，从而调控Vav1/Rac信号轴的活性转换效应，证实了c-Abl激酶对Rac1下游细胞骨架重塑信号转导通路Rac1-PAK1-LIMK1-Cofilin的调控作用，揭示了在生理剪切应力作用下以c-Abl为核心的调控中性粒细胞爬行的信号转导机制。本项目的实施不仅在细胞运动的分子细胞生物学研究方面具有重要的理论价值，同时也为炎症相关疾病的干预与治疗提供潜在的药物作用靶点。